Foam-reinforced Thermal Insulation for High Temperature and Cryogenic Temperature Applications

Ultramet has developed a highly insulating and lightweight thermal protection material composed of open-cell carbon or ceramic foam with an ultralow-density aerogel filler. The foam serves as an easily machinable structural reinforcement for the low-strength aerogel insulator and defines the shape of the component. The aerogel exists in discrete cells and is supported by the foam skeleton. The combined density of the composite insulator is as low as 0.1 g/cm3, and the thermal conductivity is <1 W/m•K at 2000°C. Aerogel-filled foam has also been shown to be beneficial for cryogenic insulation applications. Single panels up to 30” square are feasible and can be press-fit over complex features. The benefits of reinforcing chopped fiber phenolic ablators with structural foam has also been demonstrated in arcjet testing to heat flux levels of >1000 W/cm² in which low erosion rates and heat transfer were indicated. The foam helps retain the surface char layer by physical reinforcement, and the network of passages allows pyrolysis gases to escape with minimal disruption of the char layer.  Processing and testing of foam-reinforced thermal insulation will be discussed.